Over the years user demand for higher data transmission rates have led to the adoption of optic fiber technology for residential customers of Internet service providers (ISPs)/data network communications carriers. The day has passed where download rates of less than a megabit are considered satisfactory for most residential customers. Instead, the need to carry one or more streams of high definition video has led to wide demand for multiple download data rates of 10 megabits or more.
Such demand cannot be met without substantial cost. The discussion herein focuses upon the costs associated with the physical optic fiber distribution infrastructure comprising a set of serially connected optic fiber tap assemblies carrying high speed data from ISPs to residential customers. Optic fiber distribution networks, while capable of carrying substantially higher volumes of data in comparison to copper wire technologies, are also substantially more expensive to build and repair.
One of the most vital aspects of providing high speed data communications connectivity is maintaining nearly continuous service. In the case of a rare service disruption, normal operation must be quickly restored. However, the cost for added assurance against consumer dissatisfaction arising from lengthy data network communications service outages is extremely high.
One of the most important events to avoid is cutting an optic fiber distribution line providing high speed data network connectivity to a substantial number of customers. To avoid instances of cutting optic fiber, during an initial build-out of an optic fiber sub-network, a series of bores, channels, and/or trenches are formed. Thereafter, optic fiber is fed/laid, either with or without protective conduit, at a sufficient depth to ensure against damage to the optic fiber during subsequent activities of others—e.g., trenching operations associated with laying utility lines. For this reason, optic fiber distribution lines are buried several feet below grade. Moreover, where a risk of cutting the fiber is high, the optic fiber is placed within the buried conduit. The relatively deep placement of fiber distribution lines, from which one or more residential drop fibers branch at a final stage of an optic fiber, provides a higher level of confidence that the distribution fiber will not be damaged by digging, excavating or other activities within the vicinity of the distribution lines.
On the other hand, relatively inexpensive short-depth plowing, to a depth of about a foot, and then laying optic fiber in the resulting valley, enables relatively low-cost initial laying of an optic fiber distribution line in comparison to horizontal bore drilling and deep trenching approaches for laying optic fiber distribution lines. However, such initial cost savings are offset by a substantially heightened risk of costly subsequent damage to the optic fiber over the lifetime of the distribution sub-network.
In that regard, repairing a cut optic fiber line typically involves a complex fiber splicing operation. During the splicing operation, the two ends of adjoined optic fibers are heat-fused in a portable clean room environment. The cost of splicing a single broken optic fiber is thousands of dollars. Moreover, the repair process requires use of specialized tools in the hands of an expert. In that case, it may take days for such repair. In the mean time, a data network service provider must deal with irate customers without high speed data communication services for several hours—if not days—while waiting for completion of repairs to a cut optic fiber.
Ensuring the long-term satisfaction of residential customers is a multifaceted endeavor. First, the high speed data service connectivity must be reliable. Second, in the case of connectivity interruptions, service must be quickly restored. Third, the high speed data communications network connectivity must be provided at a reasonable cost. The last of which, in many cases, is only possible if the initial build-out costs are not excessive.
Another aspect of optic fiber distribution sub-network designs is the forming of leaves corresponding to individual residential network interface units. One type of signal distribution element is a splitter that provides a 1 to N distribution at a splitter point (either at a hub or a downstream local distribution point). Alternatively, a series of optic fiber tap assemblies, joined by optic fiber, take a specified portion of input signal power, which is less than half (e.g. 10 to 50 percent) of an input optical power. The remaining optical power is passed along to the next tap assembly on the series of optic fiber tap assemblies of a single optic fiber distribution line.